Those requirements are plenty.
What you are probably experiencing is that you may be on a 32-bit Windows Operating system. LR requires a 64 bit operating system.
Just subscribed (Lightroom + Photoshop 20gb) and when i try to download the new Lightroom CC it says my pc doesnt have the minimum requirements to install that.. But i have it all !
Win 7 Ultimate SP 1
Intel Core i5-4670K 3.40 ghz
Nvidia GTX 770
The new Lightroom CC (NOT Lightroom Classic) requires Windows 10. It will not run on Windows 7.